NAME

SYNOPSIS

DESCRIPTION

The setenv() function adds the variable name to the environment with
the value value, if name does not already exist. If name does exist in
the environment, then its value is changed to value if overwrite is
non-zero; if overwrite is zero, then the value of name is not changed.
The unsetenv() function deletes the variable name from the environment.

RETURN VALUE

The setenv() function returns zero on success, or -1 if there was
insufficient space in the environment. The unsetenv() function returns
zero on success, or -1 on error, with errno set to indicate the cause
of the error.

ERRORS

EINVAL name contained an '=' character.

CONFORMING TO

4.3BSD, POSIX.1-2001.

NOTES

Prior to glibc 2.2.2, unsetenv() was prototyped as returning void; more
recent glibc versions follow the POSIX.1-2001-compliant prototype shown
in the SYNOPSIS.

BUGS

POSIX.1-2001 specifies that if name contains an '=' character, then
setenv() should fail with the error EINVAL; however, versions of glibc
before 2.3.4 allowed an '=' sign in name.